This disclosure relates generally to magnet assemblies and methods for making the same. More particularly, this disclosure relates to low eddy current superconducting magnet assemblies and methods for making the same used in such application as for Magnetic Resonance Imaging (MRI) systems, as well as security and inspection technologies.
MRI systems are widely used in medical community for imaging items such as tissue and bone structures. In current applications, some MRI systems employ superconducting magnets to generate strong, uniform magnetic fields within which patients or other subjects are placed. Magnetic gradient coils and other elements such as radio frequency coils are also employed to cooperate with the superconducting magnets to produce desired images.
In such MRI systems, superconducting magnets are generally magnetically shielded to prevent the magnetic fields created by such magnets from adversely interacting with electronic equipments located near the superconducting magnets, some of which may adversely affect the imaging quality. Techniques for magnetically shielding such magnets include active and/or passive shielding.
Passively shielded superconducting magnets are employed in some applications since passive shielding is typically more cost-effective than active shielding. Passive shielding generally employs iron shields (iron yokes) for shielding of the superconducting magnets. However, in such MRI systems, magnetic gradient coils produce gradient magnetic fields so as to induce undesirable eddy current in the iron shields, which are disadvantageous to the quality of images retrieved by such MRI systems.
Therefore, there is a need for new and improved superconducting magnet assemblies and methods for making the same to reduce eddy current in Magnetic Resonance Imaging systems.